1. Field of the Invention
The present invention relates to an intra-vascular device and method. More particularly, the present invention relates to a delivery system for deploying endoluminal prostheses within the lumens of the body and to a method of using the same.
2. Description of the Related Art
Vascular aneurysms were the result of abnormal dilation of a blood vessel, usually resulting from disease and/or genetic predisposition, which weakened the arterial wall and allowed it to expand. While aneurysms could occur in any blood vessel, most occurred in the aorta and peripheral arteries, with the majority of aortic aneurysms occurring in the abdominal aorta, usually beginning below the renal arteries and often extending into one or both of the iliac arteries.
Aortic aneurysms were commonly treated in open surgical procedures where the diseased vessel segment was bypassed and repaired with an artificial vascular graft. While considered to be an effective surgical technique, particularly considering the alternative of a usual fatal ruptured abdominal aortic aneurysm, conventional vascular graft surgery suffered from a number of disadvantages. The surgical procedure was complex and required experienced surgeons and well-equipped surgical facilities. Even with the best surgeons and equipment, however, patients being treated frequently were elderly and weakened from cardiovascular and other diseases, reducing the number of eligible patients.
Even for eligible patients prior to rupture, conventional aneurysm repair had a relatively high mortality rate, usually from 2% to 10%. Morbidity related to the conventional surgery includes myocardial infarction, renal failure, impotence, paralysis, and other conditions. Additionally, even with successful surgery, recovery took several weeks, and often required a lengthy hospital stay.
In order to overcome some or all of these drawbacks, endovascular prosthesis placement for the treatment of aneurysms has been used. Although very promising, many of the proposed methods and apparatus suffered from undesirable limitations. In particular, accurate delivery and placement of the endovascular prosthesis within the vasculature was problematic.
Stent-grafts (endovascular prosthesis) are resilient structures, usually biased to expand against the surrounding lumenal wall. Such resiliently-expanding stent-grafts were tightly compressed within the catheter, imposing significant radial expansion forces against the surrounding catheter sheath. This often lead to excess friction between the stent-graft and the sheath, particularly when the resiliently-expanding structure invaginated into the catheter material. Thus, the delivery system had to be capable of imparting a significant, yet controlled, force to retract the sheath and deploy the stent-grafts.